Speed-changing mechanism.



F. JOHNSON. SPEED CHANGING-MECHANISM.

' APPLICAHON FILED SEPT. 22. 1913. 1,265,668., Patented May 7,1918.

5 SHEETS-SHEET! WITNESSES:

v INVENTOH F. JOHNSON.

SPEED CHANGPNG MECHANISM.

APPLICAIJON FILED SEPT. 22. 1913.

Patented. May 7, 1918.

5 SHEET$SHEET 2.

; dwwfk M,

A ORA/EV F. JOHNSON.

SPEED CHANGING MECHANISM.

APPLICATION FILED SEPT. 22. 1913.

Patented May 7,1918.

5 SHEETS-SHEET 3 5% 5 5:2: I ,3 5 S Q5 S. a. +2 6 5 6 g k i l A: V&

WITNESSES:

F. JOHNSON.

SPEED CHANGING MECHANISM.

APPLICATION FILED SEPT=22.1913.

Patented May 7, 1918.

F. JOHNSON.

SPEED CHANGING MECHANISM.

APPLICAHON man SEPT. 22. 1913.

Patented May 7, 1918.

5 SHEET S-SHEET 5- I/Vl/ENTOR WITNESSES:

AT OR/VEY L 1. AT Q ii SK Jamison,

OF DETROIT, MICHIGAN, ASSIGNOR T0 CADILLAC MOTOR CAR COM- OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

SPEED-CHAN GIN G MECHANISM.

Specification of Letters Patent.

Application filed September 22, 1913. Serial No. 790,997.

To all whom it may concern:

Be it known that I, FRANK JoHNsoN, a citizen of'the United States, and a resident of Detroit, in the county of Wayne and State of Michigan,

tioned at any time prior to the changing of the transmission gears.

This invention consists in combination with an indicator and a plurality of movable selector cams connected thereto, of a transmission gear shifting device comprising an operating member and a series of controllers adapted to engage the'selectors, and gear shifters operated by said actuating member whenever their respective controllers are properly positioned by the selector.-

In the accompanying drawings Figure 1 is a side elevation of the transmission case and of the case for the controlling mechanism. Fig. 2 is a vertical section thereof parallel to the plane of Fig. 1. Fig. 3 is a vertical section on the line 3-3 of Fig. 2 on a larger scale. Fig. 4 is a horizontal section on the line 44 of Fig. 2. Fig. 5 is a diagrammatic View of the selector cams. Fig. 6 is a plan of a steering wheel of an automobile showing the indicating and positioning device. Fig. 7 is a detail of the reversing gear and shifter. Fig. 8 is a diagram illustrating the relations of the shafts within the transmission case i Similar reference characters refer to like parts throughout the several views.

This invention is designed to' facilitate the changing or the reversing of the speed of power-driven vehicles, and consists generally of an indicating device comprising a movable member which can be shifted by the driver in conjunction with a scale which has characters indicating the relative speed and direction of movement. Fig. 6 shows how this device may be preferably mounted at the head of the steering post above the steering wheel. The changing of the gears.

.and thereby of-the speed or direction of during the first portion of have invented a new and Improved Speed-Changing Mechanism,

clutch pedal of the vehicle, which pedal its forward movement disengages the engine from the transmission gears and then, if desired, shifts the gear already in engagement to neutral position. At the beginning of the return movement of the clutch pedal the selected gears, if the speed or direction is to be Chan ed, are shifted into engagement, and during the last portion of the return movement of the clutch pedal, the clutch is permitted to connect the crank shaft to the transmission gears so .that the engine will be immediately coupled to the driving axle.

In the accompanying drawings, especially in Figs. 1 and 2, 6 is the crank shaft of the engine to which is connected the drum 7 having a clutch ring 8. A transmission case 9 carries ball bearings 10 for the transmission main shaft 11, which connects to the propeller shaft 12 by means of a universal coupling 13, and the propeller shaft connects to the rear axle of the vehicle in Patented May a, rare.

cally with the crank-shaft 6 by means of the ball bearing 25.

On the outer end of the cross-shaft 23 (Fig. 1) is secured a crank-arm 27, which connects to the crank-arm 28 on the shaft 29 by means of a link 30. To this shaft may be secured the clutch-pedal 32 of any desired construction and the crank-arm 33 which carries a pin 34 that extends through a slot 35 in the forward end of the link 36.

The rear end of the stub shaft 15*is enlarged and formed to constitute the gear 37 that meshes with the gear 38 on'thc countershaft 39. Secured to this counter-' shaft are gears 40, 41 and 42. The front end 44 of the shaft 11 is journaled in roller bearing 45 in the rear end of this stub shaft 15. On the shaft 11 is slidably s lined the clutch member 46 having interna teeth 47 that are designed to engage the complementary teeth 13 on the rear end of the stub shaft 15. It Will be noticed that When this clutch member 16 is moved to the right in Fig. 2, which is tovvarc the :tront ot the vehicle, that the stub shaft 15 and the shafts 11 and 12 will all he in direct engagement and revolnhle at the same speed. But it this clutch inernher is is slid back until its gear teeth engage With the gear 10 on the conntersha ft 39, then the gear 37 on the inter-mediate shaft 15, which is in constant engagement with the gear 38 on the countershaft, Will drive this shaft 11 through the countershaft, the 10 and the gear '50 at a somewhat slower speed than the speed of the crankshaft. These tivo speeds are known as the fourth and third speeds re spectively.

Slidahlysplined on the shaft 11 are two connected gears 52 and 53, adapted respectively to meshivith the gears 11 and 12 onthe counter shaft. l fhen these gears 52 and 53 are shifted to the right until the gear 52 engages the gear 11, the clutch 16 being in the position shown in 2, then the intermediate shaft 15 Will drive the shaft 11 through the gears 37, 38, 11 and 52; but when the gear 53 is in engagement with the gear 12, then the countershart will drive the shaft 11 at its slowest speed. These two are known as the second and first speeds of this transmission, respectively.

Loosely slidalole and revoluhle on the reversing gear shaft 5- mounted in the case as shown in Figs. '1 and 6, are the connected reversing gears and 56. These gears are shifted to the right, in Fig. 2, toward the engine in the ordinary vehicle, until the gear 55 meshes with the gear 53 and the gear 56 meshes with the gear 12 The other gears remain in the positions shown in Fig. 2. This engagement of the gears 1-256-55- 53 will cause the shaft \11 to turn in the opposite direction from the shaft 15. The relative locations of the shafts 11, 30 and 51' are indicated in Fig. 3. The details of the transmission thus far described torni no part of the present invention, and any other proper transmission may he substituted therefor.

The gears of this transmission may be shifted by means of the rods 60, 61 and for respectively the reverse, thelst and 2nd, and the 3rd and 1th speeds. It will be notec that only one of these rods should he shifted at any time from its neutral position, shown in Fina and for this reason, they areproeh grooves 6 1, into which the ends 5 i 9. 1.,

or the interlocking bolts 6- ivhen the next adjacent s These rods are slidah e in transverse 6i and 63 in th 'e 9.

ifilftlflnl case ends 01 these pins enter the grooves 61 and holes 73 in these rods to hold them in any desired position. Collars 7 1, '75 and 1'6 on these rods carry the forks 7T, 78 and 79, respectively, whereby the gears are connected to the rods.

These rods 62, 61 and connect to links 31, 32, '33, 31 and 85, which connect to the collars 86, 37, 88, 89 and 90, respectively, of the selector carns91, 92, 93, 91 and 95, respectively, of the -1th, 3rd, 2nd, lshand reverse speeds, respectively, by means of pins 96 that pass through the lugs 9'2 on these collars.

@onnected to the case 9 of the transmission is the case 33 of the selecting mechanism, which carries the bearings 99 and 100 the gear shitting mechanism. Attached to this case 98 is a small case 101 for a connecting gear.

The connecting rod 36 attaches to an arm 102 (Fig. on the end of the hub 103 of the gear shifting drum 10%, to which is secured a head 105 having a hub 106, journaled in the bearing 100. Rods 107 extend through holes in this drum and act as pivots for the dogs 103 mounted in pockets out in the drum in the transverse planes of the collars 86 to 90 inclusive. These collars may he held in position by springaings 103. These dogs 108 are provided with inwardly turned noses 110 and tails 112 (Fig. 2) -Wl1ll6 compression springs 113 are mounted between the tails of the dogs and the part 11-1 or the drum. The collars 86 to 90 inclusive are provided will notches 115 and 116, the shoulders of Which are shown to be about sixty degrees apart.

The selector is composed of a series of earns 91 to 95 inclusive, secured together by means of bolts 118 which pass through the holes 119. The cam 91 has a stem 120 extending through the hub 106 of the drum 10-1, and journaled in the bearing 121 car-v ried by disease 101. The earn 95 has a trunnion 123 journaled in a bearing sleeve 12s in the hub 103 or the drain 104%. ()n the stern 120 is secured a gear 125 that meshes with the segment 126 connected to the shaft 12? mounted in the hearing sleeves 123 and 129, carried by the case 101.

Mounted-on the shaft 127 is a crank arm 130 which connects to the crank arrn 132 by means or he link 133. This crank arm 132 is mounted and turned in any desired manner, but is preferably connected to the lower end of a shaft 13% mounted in the steering post, and an indicator 135 is preterahly secured to th upper end of this shaft. 11-1 notched segment 136 may he secured to the steering post above the Wheel 137 and he provided with notches opposite the charof its movement and the collar 90 is turned lector cams may therefore be properly positioned, according to the position of the indicator 135.

The angular movement of the indicator will be multiplied by the gear 125 and segment 126, and, while any desired movement of the indicator andselector may be provided for, the mechanism shown, is so constructed that a movement of the indicator from N to R will turn the selector thirty degrees to the left. By swinging the indicator to the notches marked 1, 2, 3 or 4, the selector will be turned thirty, sixty, ninety, or one hundred and twenty degrees, respectively. The different viewsshow the selector' at neutral position.

Referring now to Fig. 2, it Will be remembered that the drum 104 is turned by the arm 102 and carries the dogs 108 with it. The distance is about thirty degrees, first to the right and then to the left. All the selector 'units are shown in Fig. 5 in neutral-position, and it will be seen that at the beginning of their movements, each of the teeth 110 of the upper dogs will drop, if it has not already dropped, the tail of each dog being swung out by its spring 113. If the .3rd speed gears are in engagement, the rod 62 will be at the left end of its movement and the collar 87 will be turned to the left nearly thirty degrees and the collar 86 the same distance to the right. At the movement of the crank arm 102 to the right, the'upper dog 108 will immediately engage in the notch 115 of the collar 87 and turn it to the right, to the position shown in Fig. 2. This movement of the collar 87 will result in the collar 86 being turned an equal distance to the left, because of the connection of the two collars to the rod62 by means of the links 81 and 82.

In a similar manner, should the rod 62 and the gear-clutch 46 be in their 4th speed position, that is, at the right end of their movement, the collar 86 will have been turned to the left, and will be turned back to the right by means of its upper dog 108 and by the drum 104 to shift the gear-clutch to neutral. The same action occurs when the 1st and 2nd speed gears are to be shifted to neutral position. When the reverse gears are in mesh, the rod 60 is at the right end to the left. Therefore, when the selector is at neutral position, the upper dog will turn its collar to the right and slide the reverse gears to the position shown in Fig. 2.

It will be evident that if the transmission gears are set for any speed and it is desired to change to another, that the gears in mesh must be shifted to neutral. To effect this, the various cams shown in Fig. 5 are provided with high and low portions. In considering this mechanism it may he remembered that the cams shown in Fig. 5 turn in the'same direction to and from neutral as the indicator 135 in Fig. 6}

If now the reverse gear is in mesh and it is desired to change to the 1st speed, the indicator is swung to the notch 1. This will turn the selector cams thirty degrees to the right from the positions shown in Fig. 5, and turn the cam 94 until the lined-d is vertical. The cam 95 will also be turned thirty degrees to the right. At the forward movement'of the arm 102 and the turning of the drum 104 to the right, the nose of the upper dog of the cam 94 will ride on the hlgh part 140 of this cam and the dog will have no effect on the collar 89, but the nose of the upper dog of the reverse cam 95 will ride on the low portion 141 of the cam and its tail will engage the notch 115 of the collar and turn this collar to the right and so shift the reverse gears 55 and 56 to the left, that is, to neutral. At the end of this movement, the tail of the lower dog of the cam 94 will reach the notch 116 of the collar 89, and as the nose of this dog is nearly against the low portion 142 of the cam 94, the collar 89 will be turned to the left, forcing the rod 61 to the left and the gear 53' into mesh with the gear 42 on the countershaft.

The cam 93, which cotirdinates with the collar 88, is so formed that its lower dog is held out of engagement with its notch 116 during the time the rod 61 is being shifted by the arm 102. When the cam 93 is turned until its line (-0 is vertical, then the noses of the upper dogs of all the units except 93 engage low portions of their respective cams and thus shift the rods 60, 61 or 62 to neutral if not already there. At the return of the arm 102 the nose of the lower dog rides on the low portion 143 of the cam 93, and its tail will engage the notch 116 of the collar 88, turning the collar to the left and forcing the rod 61 to the right by means of the link 83, thus obtaining second speed.

When the third speed is desired, the selector is turned until the line b-b is vertical in Fig. 5. This brings the low portion 144 of the cam 93 under the nose of its upper dog, and as the collar 88 had been left turned to the right. when the arm 102 is swung. the tail of this dog will engage the notch 115 and the collar will be turned to neutral position. In this case as in all others, the upper dog returns the collar to neutral position.

The lower dog always does the positioning. As the 3rd speed is desired, the upper dog of cam 92 willride inoperatively on the high portion 145 of this cam, so that, if the 3rd speed were already in use. it would not be brought back to neutral. But on the return stroke, the nose of the lower dog will ride on the low portion 146 of this cam and the tail of the dog will engage in the notch 116 of the collar 87 and turning this collar to Ell the left, pull the rod 52 to the left, thus ole-- teining third speed.

In a similar manner the nose or the lower dog or" cam 91 Willride in the low portion 14-? and therefore engage the notch 3.16 of the collar 86, forcing the rod 6:2 to the right. lt will now he observed that all the upper clogs should be operative durinc' the for Word or neutralizing increment or the actuating mechanism except that or the com selected. This means that each corn. hos o. low portion extending sixty degrees to the right of the vertical line when the coins ere in neutral position, and one hundred twenty degrees to the left of said line, excepting that each coin has its own high portion, thirty degrees in length, projecting up this low portion, on which the nose its upper cog rides during the time the corn is operative, so as to prevent the dog shifting its own. gears back to neutral. ii tions are that portion 152 of i the com 91 l etween the line o-o :nd i low nortion 1&9 of this earn, the port 1;-

oi the com the part 150 of the earn 93, the "port O of the corn 9%, and the t iirt" degrees or i port 151 of the corn 9;; at the upper right hand next the line e-c.

Similarly, 11 e nose of the lower dog of each coin most he held out on all come hut il portions of earns '21 order to orerent tn tails ofthe dogs engaging the notches 116 or their respective collars, and s low portion thirty degrees in length must ee proi'ideo in each core to 13191- e one Selected by l nigh :nit such engagement. is the low portions the cams occupy one hundred eighty degrees, with the exception of thirty degrees of high portions, so the high portions occupy the some distances with the one Li P thirty degrees 1 i low ooons ire the occiirs only w niecl'ionisn: is gir l the positioning; the se c onls 21 the return octuating echnnisni,

To lone the e icle is run: i.

t indicator, on? back [he =clutcl alt-ll is i as, for

ouge no 1 US and any fixed support. This spring will normally shift the gears in advance of any thrust from the crank arm 33. But in case the shifting gears should he so positioned that their teeth abut end to end with the cooperative genre, the jamming action oi the (U111 33 will assistthe spring 156 to cause the ends of the teeth to en nge, after which the sp ing 156 will continue to slide the shifted gears along to full engagement. The propel-lions and adjustments or the parts i are such that the main clutch of the engine 1 no begin to engage until the shiited eears have about one-half the lengths of the teeth of cooperative gears.

he details and proportions oi this .1, -Y 1 n HIEL cnisrn 11121;, all he cnsngec by soled automobile engineers TlillOUi? departing from the spirit of my invention.

I clai 1. In El speed changing mechanism, the

combination of an inoicetor, a selector connee d thereto and comprising a series of cams, an actuator, and a series of operating devices each embodying an element positioncd b} said selector for shifting proper gears to toe positions specified by the indicator.

In a speed changing mechanism, the combination of a plurality of gear shifting rods, each adapted to be shifted longitudinally in both directions from neutral position, operutinc' devices for shifting said rods, euch embodying a revoluhle collar and a connecting rod, :1 revoluole actuator, 21 series of pairs of dogs carried thereby, one

for each operating device, one dog of each pair adopted to move a shifting rod to neutrs position and the other dog to more said ZMl and the gears connected thereto to operllilV-S posit on, and selecting mechanism for does.

szuo

ii. n n

speed changing mechanism, the plural-r 3, ol

Jed to 1B shifted longitudiircctions neutral posioevices shitting sa d v dying a reroiohle collar and a connection roo, t rei'oliihle actuator, a

so: of pure o1 dog's carried therein, one pair for each operating "er ice, one dog of en. ted to more ev shifting rod on and the other dogto more srs connected thereto to and c sin to e position,

coir or :lected gears to oper pair :1

4. In a speed changing mechanism, the

combination of a plurality of gear shifting rods, each adapted to be shifted longitudinally in both directions from neutral position, operating devices for shifting said rods,

each embodying a revoluble collar anda connecting rod, a revoluble actuator, a series of pairs of dogs carried thereby, one pair for each operating device, one dog of each pair adapted to move a shifting rod to neutral position and the other dog to move said rod and the gears connected thereto to operative position, a selecting mechanism for said dogs, and an indicator for positioning the selecting mechanism.

5. Ina speed changing mechanism, the combination of a' plurality of gear shifting rods, each adapted to be shifted longitudinally in both directions from neutral position, operating devices for shifting said rods, each embodying a revoluble collar and a connecting rod, a revoluble actuator. a series of pairs of dogs'carried thereby, one pair for each operating device, one dog of each pair adapted to move a shifting rod to neutral position and the other dog to move said rod and the gears connected thereto to operative position, a selecting mechanism for said dogs, an indicator for positioning the selecting mechanism, and a graduated bar adjacent said indicator 6. In a speed changing mechanism, the combination with a plurality of rods for shifting the transmission gears of a vehicle, links for shifting each of said rods and the gears connected thereto to and from neutral position, collars to which said links are connected, a revoluble actuator, dogs carried thereby, and a selector for positioning said dogs and thereby determining the collar to be revolved and its direction of revolution.

7. In a speed changing mechanism, the combination with a plurality of rods for shifting the transmission gears of a vehicle, links for shifting each of said rods and the gears connected thereto to and from neutral position, collars to which said links are connected, a revoluble actuator, dogs carried thereby, and a'selector for positioning saiddogs comprising a series of connected cams, one for each link, which cams determine the collar to be revolved and its direction of revolution.

8. In a speed changing mechanism, the combination with a plurality of rods for shifting the transmission gears of a vehicle, links for shifting each of said rods and the gears connected thereto to and from neutral position, collars to which said links are connected, a revoluble actuator, dogs carried thereby, a selector for positioning said dogs and thereby determining the collar to be revolved and its direction of revolution, and an indicator forpositioning said selector.

9'. Ina speed changing mechanism, the

combination with a plurality of rods for shifting the slidable gears of a vehicle transmission, of a pair of links connected to each of said rods, each link of each pair adapted to shift the rod and gears connected thereto longitudinally into engaging position at one side of neutral, a revoluble collar connected to each link, a drum on which said collars are mounted, engaging members for each collar-mounted on the drum, a selector to predetermine the collar and its direction of movement by said drum, and means to oscillate the drum.

10. In a speed changing mechanism, the combination with a plurality of rods for shifting the slidable gears of a vehicle trans mission, of a pair of links connected to each of said rods, each link of each pair adaptedto shift the rod and gears connected thereto longitudinally into engaging posit1on at one side of neutral, a revoluble collar connected to each link, a drum on which said collars are mounted, engaging members for each collar mounted 'on the drum, a selector to predetermine the collar and its direction of movement by said drum, means to oscillate the drum, and an indicator connected to the selector to position the same.

11. In a speed changing mechanism, the combination with the gear shifting rods of a vehicle transmission mechanism, interlocklng means to prevent the actuation of more than one rod at a time, connectors between the operating device and the shifting rods, and a selector to determine the action of the operating devices.

12. In a speed changing mechanism, the combination with a plurality of gear shifting rods of avehicle transmission mechanism adapted to be moved longitudinall either way from neutral position, an inter ock between said rods to prevent more than one rod being moved from neutral position, an operating device comprising a pair of links for each rod and a collar for each link, said links of each pair adapted to move their respective rods in opposite directions from neutral, a drum on which the collars are mounted, a pair of dogs for each collar mounted on the drum, each dog adapted to turn the collar and shift a rod in one direction, and a selector concentric with the collars and drum to control the operation of the dogs. 13. In a speed changing mechanism, th

combination with a plurality of gear shift-- rod being moved from neutral position, an-

operatingdevice comprising a pair of links for each rod and av collar for each link, said links of each palr adapted to move their respective rods in opposite directions from L130 an operating device,

neutral, a drum on which the collars are mount a pair of dogs for each collar mounted on the drum, each dog adapted to turn the collar and shift a rod in one direction,'a selector concentric with the collars and drum to control the operation or the dogs, means for positioning said selector.

ll. a speed changing mechanism, the combination with a plurality ot gear shift: ing rods of a vehicle transmission adapted to he moved longitudinally either Way from neutral position, an interlock between said rods to prevent more than one red being moved from neutral position, an operating device comprising a pair or links "for each rod and a collar for each linlr, said links each pair adapted to move their respective rods in opposite directions from neutral, a drum on which the collars are mounted, a pair of dogs for each collar mounted on the drum, each dog adapted to turn the collar and shift a rod in one direction, a series of cams, one for each co lar, mounted concentric with the drum to control the opera" n or the dogs, and an indicator to position one cams,

15. In a speed changing device, the combination or an indicator, a plurality of selector cains connected thereto, and a transmission-gear shifting device comprising an operating member, a series of controllers adapted to engage the selectors, and gear engaging members actuated by said operating member whenever the QTOPQT controllers have been properly positioned by the selector.

16, in a speed changing device, the cornbination of acase, transmission gears therein, rods for shifting said gears slidably in the case and provided with circumferential grooves which are in line when the rods are in neutral position, interlocking hare slidable in the case transversely to the rods hav: ing pointed ends adapted to enter said grooves and to prevent the increment oi: more than one rod from neutral position one time, a revoluhle actuator, a series of collars mounted thereon, one for each direction in which each rod is movable from neutral position, connectors mounted on the actuator and adapted to engage said collars, and a selecting device to position said connect-ors.

17. In a speed changing mechanism, the combination with the rods for shifting the transmission gears of a vehicle, links -for shifting said rods, one for each direction in which each rod is movable from neutral position, a hollovv operating drum having a series of pairs of transverse slots, longi tudinal pivot rods extending across he slots,

dogs mounted in said slots on said pivot rods and constituting pairs, a collar inounted on he drum in the plane of each our of dogs and formed to he by e links connecting the collars to the gear shift ing rods, a selector for determining the dogs to he moved to operative position, the rod to be shifted, and the direction of its movement.

18. In a speed changing mechanism, the combination with the rods for shifting the transmission gears of a vehicle, links for shifting said rods, one for each direction in which each rod is movable from neutral position, a hollow operating drum having a series oi pairs of transverse slots, longitudinal pivot rods extending across the slots, dogs mounted in said slots on said pivot rods and constituting pairs, a collar mounted on the drum in the plane of each pair of dogs and formed to he engaged by the dogs,

links connecting the collars to the gear shit" ing rods, a rotatable selector mounted Within the drum and engaged by the dogs to predetermine the positioning of the dogs, the gear shitting rod to be moved and the direction of its movement. i

19. In a speed changing mechanism, combination with the rods for shifting the transmission gears of a vehicle, linlrs for shifting; said rods, onelor each direction in which each rod is movable from neutral position, a hollow operating drum having a series of pairs of transverse slots, longitudinal pivot rods extending across the slots, dogs rnounted in said slots on said pivot rods and constituting pairs, a collar mounted on the drum in the plane or each pair of dogs and formed to he engaged hy the dogs, links connecting the collars to the gear shittrods, a rotatable selector mounted Within the drum and engaged by the dogs and consisting oi a series or cams united side by said cams having high and lOW porthe trons the same length, to predetermine the positioning oi the dogs, collars and gear shitting rods,

20. In a gear chang g device, the coin ination of plurality c gear shitting rods, each adapted to be shifted longitudinally in both directions from neutral position, operating devices for shifting said rods, each ern'food ving a revoluhle collar and a connecting' rod, a revoluhle hollow drum, a series of pairs at dogs carried thereby, one pair "for each operating device, one dog of each pair adapted to move a shifting rod to neutral position and e other dog to move said rod the gears connected th reto to operative position, and a rotary selector mounted Within said drain.

2i. In a gear changing device, the combiof a plurality of gear shitting rods, each adapted to he shifted longitudinally in both directions from neutral position, operating devices for shifting said rods, each embodying a revoluhle collar and a connecting rod, a revoluhle hollov; drum, a series for each operating device, one dog of each pair adapted to move a shifting rod to neutral position and the'other dog to move said rod and the gears connected thereto to operative position, and a rotary selector mounted within said drum comprising a series of cams, one for each collar, and for each pair of dogs to be positioned thereby.

In a gear changing device, the combination of a plurality of gear shifting rods, each adapted to be shifted longitudinally in both directions from neutral position, operating devices for shifting said rods, each embodying a revoluble collar and a connecting rod. a revol'uble hollow drum, a series of pairs of dogs carried thereby, one pair for each operating device, one dog of each pair adapted to move a shifting rod to neutral position and the other dog to move said rod and the gears connected thereto to operative position, a rotary selector mounted within said drum, a rotary selector mounted Within the drum and comprising a cam for each collar, said cams engaged by said dogs which are positioned by the selector, and an indicator for positioning the selector.

23. In a gear changing device, the coinbination of a plurality of gear shifting rods, each adapted to be shifted longitudinally in both directions from neutral position, operating devices for shifting said rods, each embodying a revoluble collar and a connecting rod, a revoluble hollow drum, a series of pairs of dogs carried thereby, one pair for each operating device, one dog of each pair adapted to move a shifting rod to neutral position and the other dog to move said rod and the gears connected thereto to operative position, a rotary selector mounted within said drum in engagement with said dogs to position the same, a movable indicator, means connecting the indicator and selector, and a graduated scale provided with retaining devices whereby the proper position of the indicator may be fixed for any desired speed of the gears.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

FRANK JOHNSON.

Witnesses HUGO \V. KREINBRING, L. M. SPENCER. 

